A mother who lost her husband and two children in a deliberate house fire has made an emotional appeal on television in a bid to help police catch their killer.

Thomas Sharkey, 21, died in the blaze at the family's flat in Scott Court, Helensburgh, Argyll and Bute, in the early hours of July 24.

His eight-year-old sister Bridget died on the way to the Royal Alexandra Hospital in Paisley.

Six days later, their father Thomas Sharkey Snr, 55, died of pneumonia at Glasgow's Royal Infirmary, caused by breathing in smoke from the fire.

Mr Sharkey's wife, Angela, 46, was the only member of the family to survive the blaze. She was critically injured and lay unconscious in hospital for almost two weeks before learning of her husband and children's deaths on August 4.

The unsolved triple murder inquiry featured on the BBC's Crimewatch programme, which included a reconstruction of the night of the blaze and interviews with family members.

Mrs Sharkey said: "I have no idea why anyone would want to do this to me and my family. It's just so unfair that they're gone.

"It's still sinking in, obviously. But I've got to face it. It'll be made easier if I have a reason or somebody can explain to me why they felt the need to go this far."

Mrs Sharkey recalled the moment when her sister told her of her family's deaths.

She said: "I didn't know how ill I had been, how close I was to being dead as well. I have no recollection of smoke, fire, shouting, anything. I thought 'it can't be true, I don't believe it', but I did believe it, by their faces. Then it just went downhill from there on in really."